Plastic molding machines involve the injection of heated material into a die in order to form a desired product. By necessity, fluid must be circulated through such dies, particularly, through bores in the dies, in order to maximize heat transfer between the dies and the circulating liquid. To improve fluid flow in and out of the bore, a baffle is inserted into the bore to divide the bore into separate longitudinal passages. The separate passages are intended to achieve a desired consistency of fluid flow and fluid temperature within the bore.
Such bores extend longitudinally into the die. To maximize the desired consistency of fluid flow and temperature throughout the bore, an effective seal between the separate passages formed by the inserted baffle is preferred. Due to their machined nature, bores and baffles will exhibit structural inconsistencies and will therefore be difficult to mate to achieve the effective seal. That is, the walls of the bore and the edges of the baffle must join to create a seal that will control the flow of fluid in and out of the bore. If there is a leaky seal, the fluid from the separate chambers will mix, and the baffle will not perform its intended function of regulating flow through the bore.
Baffles known in the art traditionally feature flat blade portions. Such a flat orientation generally performs the function of separating a bore into at least two passages, however, that flat structure fails in other regards. For instance, the flow of liquid against the flat baffle may cause the baffle to move from its initial position in the board such any seal between the edges of the baffle and the wall of the bore is broken. Furthermore, the flat surface is inefficient in obtaining a consistent and turbulent fluid flow in and out of the bore in that the fluid will enter the bore perpendicularly to the intended flow path. The flat surface of the baffle does little to direct the fluid along the intended flow path. Furthermore, the flat surface does little to disrupt the flow of the fluid against itself, which disruption would be desirable to increase the distribution of heat throughout the fluid.
Baffles are also often made of metal or brass materials or extruded materials. To perform properly, baffles must be measured and cut to an appropriate length so as to effectively mate with the bores in which they are to be inserted. Baffles made of metal and brass require measuring, cutting, and grinding before the baffle can be installed in a bore. Not only is this installation a time-consuming process, it can be an imprecise effort that detrimentally affects the fit and performance of the baffle within the bore.
Furthermore, baffles made of metal and brass only can only be manufactured with a flat blade. That is, the blade of a brass or steel baffle cannot have ribs or bumps that would create a non-flat surface of the blade. As discussed above, the flat blade fails to increase turbulence in the fluid passing through a bore such that cooling of the fluid is not increased. Baffles of steel and brass composition also do not permit material (e.g., rubber) to be overmolded on the surface of the steel or brass baffle, thus, such baffles cannot incorporate a rubber-edged blade to improve the seal between the baffle and the bore into which the bore inserts.
U.S. Pat. No. 43,548,863 (Stippich) discloses an elongated plastic stem with a threaded plug at one end thereof and fins radiating therefrom. The stem is screwed into the open end of a liquid circulating bore in a die to divide the bore into longitudinally extending passages and cause the liquid to flow serially back and forth within the bore. The Stippich disclosure involves fins of substantially flat orientation, which orientation does not increase the turbulence in the liquid directed by the disclosure and flowing through the bore.
U.S. Pat. No. 3,760,874 (Boskovic) discloses a heat exchange fluid baffle comprising an extruded blade. The blade comprises a main central body section that has spaced apart longitudinal edges with sufficient flexibility to bend and spread as the blade is press-fitted into a mold aperture. Boskovic likewise involves fins of substantially flat orientation, which orientation does not increase the turbulence in the liquid directed by the disclosure and flowing through the bore.
U.S. Pat. No. 4,800,953 (Veldhoff) discloses a baffle for partitioning fluid circulating passages. The baffle is held in position by resilient arms that project outwardly from the baffle and are received fully within a passage that is separate from the fluid circulating passage. While the Veldhoff disclosure is intended to improve securing a baffle in a passage, its incorporation of arms causes unnecessary complication in the installation and configuration of the baffle.
U.S. Pat. No. 5,830,515 (Pleasant, et al.) discloses mold insert including a baffle with a blade that fits within a liquid receiving bore in a plastic injection mold. Fins project outwardly from the faces of the blade in order to create turbulence in liquid flowing into and out of the bore. The '515 patent attempts to address the need for improving the efficiency of heating and or cooling of the mold insert, however, the fins of the '515 patent disrupt the flow sufficiently to require a user to increase the pressure of fluid entering the bore over the pressure otherwise required to circulate fluid into and out of a bore into which a flat-bladed baffle has been inserted. This requirement of increased pressure may require the incorporation of a compressor, which incorporation necessitates additional equipment and energy to operate the '515 invention. Similar problems are associated with the disclosure made in U.S. Pat. No. 6,168,415 to Pleasant.
U.S. Pat. No. 7,159,837 (Richards) discloses a baffle that offers acceptance of greater torque over the prior art in the installation of the baffle into a liquid receiving bore. While the Richards disclosure improves the manner in which the user can secure the baffle in the threaded receiving portion of a bore, it does not address the other problems associated with installation such as measuring and fitting the baffle into the bore.
Thus, what is needed is an improved baffle device that overcomes the shortcomings of the prior art, while at the same time improving on the existing performance of the prior art.